Self-opening die head



Nov; 9 1926. 1,606,502

A. F. BREITENSTEIN SELF OPENING DIE HEAD.

Filed June 25, 1924 2 Sheets-Sheet 1 A. F. BREITENSTEIN SELF OPENING DIE HEAD Nov. 9 1926.

12 Sheets-Sheet 2 Filed June 25, 1924 Patented Nov. 9, 1926. V

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ALBERT r. ennrrnnsrnm, on new Haven, oonnnorronr, Assisnon 'ro THE eno- METRIC TOOL 00., or new HAVEN, connncrrour, a con'ronarronb sELF oPENlNG DIE HEAD.

Application filed June 25,

I do hereby declare the following, when taken in connection with the accompanying drawings and the characters of reference marked thereon, to be a full, clear and exact description of the invention, and which said drawings constitute part of this application, and represent, in-- Fig. 1 a View in front elevation of a selfopening die-head constructed in accordance with my invention.

Fig. 2 a view thereof in side elevation.

Fig. 3 a view thereof in central, longitudinal section. I

Fig. 4 a broken, sectional view on the line 4-4 of Fig. 1.

Fig. 5 a corresponding view on the line 5-5 of Fig. 1.

Fig. 6 a broken view in front elevation of the die-head body, stripped.

Fig. 7 a detail, perspective view showing the four, segmental, chaser-retaining plates.

My invention relates to an improved selfopening die-head, whether stationary or rotary, the object being to produce a snnple, compact, convenient and durable die-head constructed with particular reference to its adaptability to be used in threading close to a shoulder, and to giving the chasers the maximum amount of support, and hence securing for them stability of position and precision of performance.

\Vith these ends in view, my invention consists in a self-opening die-head having certain details of construct-ion and combination of parts as will be hereinafter described and particularly recited in the claim.

In carrying out my invention, as herein shown, I employ four equidistant chasers 10 respectively located in as many radial grooves 11 in the face of a skeleton 12 having a hollow shank 13. The said chasers project between and are held in place by four corresponding segmental chaser-retaining plates 14 secured to the forward face of the body 12 by rivets 15, as clearly shown in Fig. 1, these four segmental plates taking the place of the ordinary annular retainingring commonly employed for holding the chasers of self-opening die-heads in place.

As herein shown, the corresponding forward corners of the chasers are cut back to form shoulders 16, over which the edges of the said plates 14 rest, so as to retain the chasers in place without interfering with their free radial movement. Under this condie-body 1924. Serial No. 722,278.

struction, the forward faces ofthe chasers may be projectedto any desired extent be yond the plane of the chaser-retaining plates 14 without weakening the support which the chasers receive from the die-body and plates.

The extension of the chasers forward between the means employed to retain them in place permits them to be used for threading a shouldered object close to its shoulder,

which cannot be done with the self-opening die-heads of the prior art without weakening the die-head structure and endangering the precision of its operation, notably in resorting to chasers of too delicate shape towithstand the work demanded of them.

As shown, the opening movement of the chasers is effected by their. provision upon their inner edges with pins 17 engaged by spring-actuated plungers 18 located in radial bores 19 in the die-head body 12, as shown in Fig. 3.

FOr moving the chasers inward into their cutting positions, their beveled outer edges 20 are engaged by the beveled forward end of an operating-sleeve 21, which rides back and forth upon an adjusting-ring 22 internally-threaded for being screwed upon the threaded portion of the shank 13 of the body 12. The sleeve 21 is guided in being so moved back and forth by two gulde-pins 23 carried by it and extending forward into bores 24 in the body 12, as shown in Fig. 5. For moving the sleeve rearward to per-nit the self-opening of the chasers, I employ two springs 26, the respective ends of which are inserted into bores 27 in the sleeve 21 and bores 28 in the body 12, as shown in Fig. 4.

For locking the sleeve in its closed position, in which the chasers are held in their advanced or cutting positions, I may employ any approved form of locking device. As herein shown, I employ for the purpose, a locking device of my invention forming the subject-matter of an application filed of even date herewith, the said device consisting of a trippingmember 29, a locking member 30, a filler-member 31, and springs 32 (only one of which is shown herein) eX- erting a constant effort to force the lock ing-member outward for its engagement with an abutment-shoulder 33 upon the interior of the sleeve 21.

I would, therefore, have it understood that I do not limit myself to the use of my improved chasers and means for mounting the same with such a tripping device as herein shown and described, nor with any particular tripping device.

I am aware that a self-opening die-head having segmental chaser-retaining plates is old, and do not claim the same broadly.

I claim In a self-opening rotary die-head, the combination with a one-piece body provided with an integral tubular shank and having its front face formed with radial chaser-receiving slots, of radially-movable chasers having sliding bearing directly in the said slots and each having one flat side and one shouldered side and each having its outer end beveled and formed at its inner end with cutting-teeth; springs for moving the said chasers radially outward, an operating sleeve axially movable with respect to the said body and engaging, at its forward end,

with the beveled outer ends of the said chasers for forcing the same inwardly when the sleeve is moved forward; and segmental chaser-retaining plates permanently fastened to the front face of the said body and positioned thereupon, so that one end of each plate is flush with one wall of one of the said radial slots therein and so that its 0pposite end overhangs the wall of an adjacent slot for engagement with the single shoulder of the chaser therein, whereby the said chasers may be inserted into and removed from the said chaser-receiving slots by retiring the sleeve from front to rear and without necessitating the removal of any of the said chaser-retaining plates or the removal from the tool of the said sleeve.

In testimony whereof, I have signed this specification.

ALBERT F. BREITENSTEIN. 

